JP2008282270A - Paper sheet discrimination device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve accuracy of detecting fluorescence, while reducing the cost. <P>SOLUTION: There provided are: a placement section 1 on which at least part of a paper sheet P is placed flatly; an ultraviolet light radiation section 2 for radiating ultraviolet light onto one surface P1 of a paper sheet placed on the placement section; a first light detection section 3 of which a light receiving surface 3a faces the other surface P2 of the paper sheet placed on the placement section, and of which the light receiving surface is arranged in parallel with the other surface so as to face the ultraviolet light radiated onto one surface of the paper sheet at an incident angle of 0 degree; an optical element 31, interposed between the other surface of the paper sheet placed on the placement section and the first light detection section, for transmitting the fluorescence emitted from the paper sheet by the ultraviolet light from the ultraviolet light radiation section, and shielding the ultraviolet light; a second light detection section 4 of which a light receiving surface 4a faces the other surface of the paper sheet so as to receive the ultraviolet light from the ultraviolet light radiation section which transmits through the paper sheet placed on the placement section; and a control section 5 for determining authenticity of the paper sheet based on a detection signal from the first light detection section and the second light detection section. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a paper sheet discrimination apparatus that determines the authenticity of a paper sheet using ultraviolet rays.

  For paper sheets such as banknotes and securities, fluorescent materials such as fluorescent ink and fluorescent fiber are used to prevent forgery. 2. Description of the Related Art Conventionally, there has been known a paper sheet discrimination apparatus that determines the authenticity of a paper sheet by detecting a phosphor using ultraviolet rays.

  A conventional paper sheet discrimination apparatus irradiates one side of a paper sheet with ultraviolet light from an ultraviolet light source, excites the phosphor of the paper sheet, and emits fluorescence emitted from one side of the paper sheet. Detect by dividing into specific wavelength ranges. This paper sheet discrimination device detects fluorescence in a specific wavelength range transmitted by an optical filter with each light receiving element, and determines the authenticity of the paper sheet based on magnitude correlation data between detection signals for each specific wavelength range. In addition, it is possible to eliminate paper sheets forged with a fluorescent pen or the like (see, for example, Patent Document 1).

  In addition, conventional paper sheet discrimination devices irradiate one surface of a paper sheet with ultraviolet light from an ultraviolet light source and reflect it on one surface of the paper sheet, and one surface of the paper sheet. Some of them detect fluorescence emitted from the. In this paper sheet discrimination device, ultraviolet rays and fluorescence detected by each light receiving element are compared with reference values, respectively, and when both standards are satisfied, it is determined that the paper sheet is true (for example, patent Reference 2).

JP 2002-109598 A Japanese National Patent Publication No. 8-505253

  However, the paper sheet discrimination apparatus shown in Patent Document 1 and Patent Document 2 receives fluorescence emitted on one surface of the paper sheet by ultraviolet light irradiated on one surface of the paper sheet. The ultraviolet light source is arranged in such a manner that ultraviolet rays are emitted from an oblique direction with respect to one surface of the paper sheet so as not to block the fluorescence received by the light receiving element. For this reason, since the distance from the ultraviolet light source to one surface of the paper sheet is long and the amount of ultraviolet light reaching the paper sheet is reduced, the amount of fluorescence emitted from the paper sheet by the ultraviolet light is also reduced. As a result, in the conventional paper sheet discrimination apparatus, the fluorescence detection accuracy at the light receiving element is poor, and the authenticity determination performance is degraded. In this case, in order to increase the irradiation amount of ultraviolet rays, an ultraviolet light source with a large current consumption is used, which causes a problem of increasing costs.

  In view of the above circumstances, an object of the present invention is to provide a paper sheet discriminating apparatus capable of improving the fluorescence detection accuracy while reducing the cost.

  In order to achieve the above object, a paper sheet discrimination apparatus according to claim 1 of the present invention includes an arrangement unit that arranges at least a part of a paper sheet in a flat state, and a paper that is arranged in the arrangement unit. An ultraviolet irradiation unit that irradiates ultraviolet rays toward one surface of the leaf, and a light receiving surface directed to the other surface of the paper sheet disposed in the placement unit, and an incident angle on the one surface of the paper sheet A first light detection unit in which the light receiving surface is disposed in parallel to the other surface of the paper sheet so as to face ultraviolet rays irradiated at 0 degrees, and a paper sheet disposed in the placement unit. An optical element that is disposed between the other surface and the first light detection unit, transmits fluorescence emitted from the paper sheets by ultraviolet rays from the ultraviolet irradiation unit, and blocks ultraviolet rays; The paper so as to receive ultraviolet rays from the ultraviolet irradiation unit that has passed through the paper sheets arranged in the arrangement unit The authenticity of the paper sheet is determined based on detection signals from the second light detection unit disposed with the light-receiving surface facing the other surface, and the first light detection unit and the second light detection unit. And a control unit.

  In the paper sheet discrimination apparatus according to the present invention, the first light detection unit directs the light receiving surface to the other surface of the paper sheet disposed in the placement unit, and the incident angle is 0 degree on one surface of the paper sheet. The light receiving surface is arranged in parallel to the other surface of the paper sheet so as to face the ultraviolet rays irradiated in step (b). For this reason, the paper sheet is irradiated on one surface at an incident angle of 0 degree, and emits fluorescence with a large amount of light by ultraviolet light that is closest to the one surface and has a large amount of light. The fluorescence with the largest amount of light is detected by the light receiving surface arranged in parallel with the other surface of the class. As a result, since the amount of fluorescence incident on the first light detection unit is increased, the fluorescence detection accuracy is improved and the authenticity determination performance can be improved. In addition, since the amount of fluorescence incident on the first light detection unit can be increased, it is possible to detect fluorescence with a sufficient amount of incident light even when an ultraviolet irradiation unit with a small amount of ultraviolet irradiation is used, or emit fluorescence. Since the consumption current of the ultraviolet irradiation unit can be suppressed so that the amount of ultraviolet irradiation is minimized, the cost can be reduced.

  In addition, the paper sheet discrimination device according to the present invention detects fluorescence emitted from the paper sheet by irradiation of ultraviolet rays by the first light detection unit, and detects ultraviolet light transmitted through the paper sheets by the second light detection unit. To do. For this reason, by detecting fluorescence, the fluorescence characteristics of the paper sheet itself and the fluorescence characteristics of the fluorescent ink and fluorescent fiber contained in the paper sheet can be acquired as determination factors, and detection of ultraviolet rays transmitted through the paper sheet Thus, the ultraviolet transmission characteristics of the paper sheet P itself, the ultraviolet transmission characteristics due to paper thickness changes such as watermarks, and the ultraviolet transmission characteristics due to printing ink can be acquired as determination factors. As a result, with a simple configuration in which two light detection units are arranged for at least one ultraviolet irradiation unit, it is possible to perform authentication determination based on a large number of determination elements, thereby improving authentication determination performance.

  Exemplary embodiments of a paper sheet discrimination device according to the present invention will be described below in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments.

  FIG. 1 is a schematic diagram showing the main configuration of a paper sheet discrimination device according to the present invention, FIG. 2 is a block diagram showing a control system of the paper sheet discrimination device according to the present invention, and FIG. FIG. 4 is a flowchart showing the discrimination operation of the paper sheet discrimination apparatus according to the present invention, and FIG. 4 is a schematic diagram showing the discrimination operation of the paper sheet discrimination apparatus according to the present invention.

  As shown in FIGS. 1 and 2, the paper sheet discrimination apparatus according to the present embodiment includes an arrangement unit 1, an ultraviolet irradiation unit 2, a first light detection unit 3, a second light detection unit 4, and a control. Part 5 is provided.

  The placement unit 1 is for placing the paper sheet P in a flat state, and is configured as a transport unit in the present embodiment. The transport unit includes a transport path 11 and a transport unit 12 as shown in FIG. The conveyance path 11 defines a conveyance area extending in the left-right direction between the upper and lower wall portions 11a, 11b facing each other in the vertical direction in FIG. The transport means 12 transports the paper sheet P along the extending direction of the transport path 11, and FIG. 1 shows a pair of rollers that rotate while sandwiching the paper sheet P. The conveying means 12 is driven by a driving source (not shown) such as a motor. This arrangement part 1 conveys the paper sheet P along the conveyance path 11 in a flat state by the conveying means 12 between the upper and lower wall parts 11a and 11b. The placement unit 1 is also provided with a paper sheet detection unit 13 (see FIG. 2) such as a photo interrupter that generates a pulse signal when the paper sheet P is placed on the transport path 11. In addition, the arrangement | positioning part 1 should just arrange | position at least one part of the paper sheet P irradiated with an ultraviolet-ray by the ultraviolet irradiation part 2 mentioned later in a flat state, and the part of other paper sheets P is not flat. Also good.

  As shown in FIG. 1, the ultraviolet irradiation unit 2 is arranged on the upper wall 11a side in the arrangement unit 1, and one surface P1 of the paper sheet P arranged flat on the arrangement unit 1 (FIG. 1). The upper surface of the paper sheet P in the middle is irradiated with ultraviolet rays. For the ultraviolet irradiation unit 2, an ultraviolet light emitting diode having a peak wavelength of 365 nm, for example, is used as the ultraviolet light emitting element. The ultraviolet light emitted from the ultraviolet light emitting diode used in the ultraviolet irradiation unit 2 contains a slight visible light component. For this reason, the upper wall 11a is interposed between the paper sheet P arranged in the arrangement unit 1 and the ultraviolet irradiation unit 2, and removes the visible light component from the light irradiated from the ultraviolet irradiation unit 2, An ultraviolet transmission filter 21 that is an optical element that transmits only ultraviolet rays is provided.

  The first light detection unit 3 uses a light receiving element such as a silicon photodiode. As shown in FIG. 1, the first light detection unit 3 is arranged on the lower wall portion 11 b in the arrangement unit 1, sandwiches the conveyance path 11 with the ultraviolet irradiation unit 2, and faces the ultraviolet irradiation unit 2. It is arranged. Specifically, the first light detection unit 3 directs the light receiving surface 3a to the other surface P2 (the lower surface of the paper sheet P in FIG. 1) of the paper sheet P disposed flat on the arrangement unit 1, In addition, the other side of the paper sheet P is opposed to the irradiation direction of the ultraviolet rays from the ultraviolet irradiation unit 2 that irradiates one surface P1 of the paper sheet P with an incident angle of 0 degree (perpendicular to the one surface P1) The light receiving surface 3a is arranged in parallel to the surface P2. The first light detection unit 3 receives the fluorescence emitted by exciting the phosphor of the paper sheet P with the ultraviolet rays from the ultraviolet irradiation unit 2.

  Moreover, since the ultraviolet light from the ultraviolet irradiation part 2 which permeate | transmits the paper sheet P will also be light-received by the light-receiving surface 3a of the 1st light detection part 3, it arrange | positions at the arrangement | positioning part 1 at the lower wall part 11b. An optical element that is interposed between the paper sheet P and the first light detection unit 3 to remove the ultraviolet light from the ultraviolet irradiation unit 2 that has passed through the paper sheet P and transmits only fluorescence (visible light). An ultraviolet cut filter 31 is provided. The ultraviolet cut filter 31 is disposed so as to be flush with the wall surface of the lower wall portion 11 b and covers the light receiving surface 3 a of the first light detection unit 3, and is a sheet of paper P that passes through the transport path 11. It also prevents clogging and adhesion of dust to the light receiving surface 3a of the first light detection unit 3.

  The second light detection unit 4 is a light receiving element such as a silicon photodiode, and is arranged on the lower wall portion 11b in the arrangement unit 1 as shown in FIG. The second light detection unit 4 is disposed close to the first light detection unit 3, and is disposed in parallel with the first light detection unit 3 in the present embodiment. The second light detection unit 4 receives the ultraviolet rays from the ultraviolet irradiation unit 2 that transmits the paper sheet P arranged in the arrangement unit 1.

  The lower wall portion 11b is provided with a protective glass 41 that is disposed flush with the wall surface of the lower wall portion 11b and covers the light receiving surface 4a of the second light detection unit 4. The protective glass 41 prevents paper jamming of the paper sheet P passing through the conveyance path 11 and adhesion of dust to the light receiving surface 4 a of the second light detection unit 4.

  A storage unit 6 is connected to the control unit 5 as shown in FIG. The control unit 5 is connected to the paper sheet detection unit 13, the transport unit 12, the ultraviolet irradiation unit 2, the first light detection unit 3, and the second light detection unit 4. The control unit 5 controls the paper sheet discrimination device using the determination information 6a acquired from the storage unit 6 according to programs and data stored in the storage unit 6 in advance.

  The control information is input to the control unit 5. The determination information 6a is a reference value for the fluorescence characteristics and ultraviolet transmission characteristics of the genuine paper sheet P. The fluorescence characteristics include the fluorescence characteristics of the paper sheet P itself and the fluorescence characteristics of the fluorescent ink and fluorescent fiber contained in the paper sheet P. The ultraviolet transmission characteristics include the ultraviolet transmission characteristics of the sheet P of the paper sheet P, the ultraviolet transmission characteristics due to paper thickness changes such as watermarks, and the ultraviolet transmission characteristics due to printing ink. The control unit 5 stores the input determination information 6 a in the storage unit 6.

  The control unit 5 includes a determination unit 5a. The determination unit 5a determines the authenticity of the paper sheet P. The determination unit 5a performs comparison with the determination information 6a based on detection signals from the first light detection unit 3 and the second light detection unit 4, and when each detection signal satisfies the criterion of the determination information 6a, It is determined as a genuine paper sheet P.

  The paper sheet discrimination operation in the control unit 5 will be described with reference to FIGS. The control unit 5 conveys the paper sheet P to the conveyance path 11 of the arrangement unit 1 by the conveyance unit 12, and when the paper sheet P is detected by the paper sheet detection unit 13 (step S1), the ultraviolet irradiation unit 2 is driven to irradiate one surface P1 of the paper sheet P placed in the placement unit 1 with ultraviolet rays U1 (step S2). Next, the control unit 5 acquires a detection signal from the first light detection unit 3 that has detected the fluorescence F emitted from the paper sheet P by the irradiated ultraviolet ray U1 (step S3), and the paper sheet P. A detection signal is acquired from the second light detection unit 4 that has detected the ultraviolet ray U2 that has passed through (step S4). Finally, the control unit 5 determines the authenticity of the paper sheet P by comparing the detection signals acquired from the first light detection unit 3 and the second light detection unit 4 with the determination information 6a (Step S5). Exit.

  In the paper sheet discrimination apparatus described above, the first light detection unit 3 faces the light receiving surface 3a to the other surface P2 of the paper sheet P arranged in the arrangement unit 1, and one surface P1 of the paper sheet P. The light receiving surface 3a is disposed in parallel to the other surface P2 of the paper sheet P so as to face the ultraviolet rays irradiated at an incident angle of 0 degree. For this reason, the paper sheet P is irradiated on the one surface P1 at an incident angle of 0 degree, and emits fluorescent light with a large amount of light by the ultraviolet light closest to the one surface P1 and having a large amount of light, and the first light detection unit 3 The light receiving surface 3a arranged in parallel with the other surface P2 of the paper sheet P receives the most fluorescent light. As a result, since the amount of fluorescence incident on the first light detection unit 3 can be increased, the fluorescence detection accuracy is improved and the determination performance can be improved. Further, since the amount of fluorescence incident on the first light detection unit 3 can be increased, it is possible to receive fluorescence with a sufficient amount of incident light even using the ultraviolet irradiation unit 2 with a small amount of ultraviolet irradiation. Since the current consumption of the ultraviolet irradiation unit 2 can be suppressed so that the irradiation light quantity of the ultraviolet rays for releasing the light is minimized, the cost can be reduced.

  Further, since the fluorescent light having a large amount of light is emitted by the ultraviolet ray having the largest amount of light closest to one surface P1 of the paper sheet P, the ultraviolet light emitted from the paper sheet P is included in the ultraviolet light irradiated by the ultraviolet irradiation unit 2. It can be obtained as sufficiently strong light compared to visible light components. For this reason, it is possible to receive fluorescence by the first light detection unit 3 without using an expensive ultraviolet light transmission filter 21 that removes a visible light component between the ultraviolet irradiation unit 2 and the paper sheet P. Become. As a result, it is possible to replace the protective glass with an inexpensive protective glass without using the ultraviolet transmission filter 21 and reduce the cost.

  In addition, in the paper sheet discrimination apparatus described above, the fluorescence F emitted from the paper sheet P is detected by the first light detection unit 3, and the ultraviolet light U2 that has passed through the paper sheet P is detected by the second light detection unit 4. is doing. For this reason, by detecting the fluorescence F, the fluorescence characteristics of the sheet P of the paper sheet P and the fluorescence characteristics of the fluorescent ink / fluorescent fiber contained in the paper sheet P can be acquired as a determination element and transmitted through the paper sheet P. By detecting the ultraviolet ray U2, the ultraviolet ray transmission characteristic of the sheet P of the paper sheet P, the ultraviolet ray transmission characteristic due to a change in the paper thickness such as watermark, and the ultraviolet ray transmission characteristic due to the printing ink can be acquired as determination factors. As a result, with a simple configuration in which the two light detection units 3 and 4 are arranged with respect to at least one ultraviolet irradiation unit 2, it is possible to determine the authenticity based on a large number of determination elements, thereby improving the authenticity determination performance. it can.

  Further, the amount of ultraviolet light transmitted through the other surface P2 of the paper sheet P is very large relative to the amount of fluorescence emitted by the paper sheet P. For this reason, in the 2nd light detection part 4, it becomes possible to receive an ultraviolet-ray, without using the expensive ultraviolet-ray transmissive filter which removes a visible light component. As a result, it is only necessary to provide an inexpensive protective glass 41 between the paper sheet P and the second light detection unit 4, and the cost can be further reduced.

  In the above-described embodiment, an example in which one first light detection unit 3 and one second light detection unit 4 are provided for each ultraviolet irradiation unit 2 in FIGS. 1 and 4 is shown. However, since the second light detection unit 4 can be disposed close to the first light detection unit 3, a plurality of second light detection units 4 may be disposed around the first light detection unit 3. .

  In the above-described embodiment, in FIG. 1 and FIG. 4, the ultraviolet light irradiation unit 2 is provided as one, and the first light detection unit 3 and the second light detection unit 4 are arranged corresponding to the ultraviolet light irradiation unit 2. However, this is not the case. For example, a direction (depth direction in FIGS. 1 and 4) perpendicular to the conveyance direction (the left-right direction in FIGS. 1 and 4) of the paper sheet P by the conveyance unit, and the width direction of the conveyed paper sheet P A plurality of ultraviolet irradiation units 2 are arranged side by side, and the first light detection unit 3 and the second light detection unit 4 are arranged corresponding to the ultraviolet irradiation unit 2, thereby intersecting the transport direction of the paper sheet P. Thus, the determination element of the paper sheet P can be detected.

It is the schematic which shows the principal part structure of the paper sheet discrimination | determination apparatus which concerns on this invention. It is a block diagram which shows the control system of the paper sheet discrimination | determination apparatus which concerns on this invention. It is a flowchart which shows the discrimination operation | movement of the paper sheet discrimination apparatus which concerns on this invention. It is the schematic which shows the discrimination operation | movement of the paper sheet discrimination apparatus which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Arrangement part 11 Conveyance path 11a Upper wall part 11b Lower wall part 12 Conveyance means 13 Paper sheet detection part 2 Ultraviolet irradiation part 21 Ultraviolet transmission filter 3 1st light detection part 3a Light-receiving surface 31 Ultraviolet cut filter 4 2nd light detection part 4a Light-receiving surface 41 Protective glass 5 Control unit 5a Judgment unit 6 Storage unit 6a Judgment information P Paper sheet P1 One side P2 The other side U1, U2 UV F Fluorescence

Claims (1)

An arrangement part for arranging at least a part of the paper sheet in a flat state;
An ultraviolet irradiation unit that irradiates ultraviolet rays toward one surface of the paper sheets arranged in the arrangement unit;
The other side of the paper sheet is disposed so that the light receiving surface faces the other surface of the paper sheet placed in the placement portion and faces the ultraviolet ray irradiated to the one surface of the paper sheet at an incident angle of 0 degree. A first photodetecting portion in which the light receiving surface is disposed in parallel to the surface of
Arranged between the other surface of the paper sheet arranged in the arrangement unit and the first light detection unit, and transmits fluorescence emitted from the paper sheet by the ultraviolet rays from the ultraviolet irradiation unit. And an optical element that shields ultraviolet rays;
A second light detection unit disposed with the light receiving surface facing the other surface of the paper sheet so as to receive ultraviolet light from the ultraviolet light irradiation unit that has passed through the paper sheet disposed in the placement unit;
And a control unit that determines the authenticity of the paper based on detection signals from the first light detection unit and the second light detection unit.

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